The Structural Biology Group within the Department of Biochemistry at Columbia University proposes to install an Evans and Sutherland Computer Graphics system. This system is necessary for the wide range of structural studies being carried out by the six Senior Investigators of this proposal. Crystallographic and theoretical studies are supplemented by information from a variety of other disciplines including electron microscopy, nuclear magnetic resonance and other spectroscopic techniques. The information obtained is complex, even for a single macromolecule, and visual presentation of the enormous volume of data is cruicial for its interpretation. All the individual research projects involve the progression from the molecular structures of isolated molecules to those of the multi-component assemblies of small biological systems. Such studies require every possible aid including that of color graphics. The major projects, in which the Graphics System will be used, are: the determination of the molecular structure of the adenovirus capsid (Burnett); the structure and function of snake venom toxins (Low); computer studies of protein structure and function (Honig); X-ray diffraction studies of filamentous bacteriophages (Makowski); structure determination of membrane proteins and lipids (Wallace); structural studies on RNA phages and QB replicase (Bricogne).